Comment by pydry
3 days ago
It'll probably be fulfilled in 3 stages
1) Gas peakers - where every kilowatt hour delivered by solar or wind is just a kilowatt hour of gas that would otherwise have been burned. We are generally still here - still burning gas while it's sunny and windy.
2) Pumped storage and batteries gets us to 98% carbon free grids with ~5 hours of storage with 90% roundtrip efficiency - https://reneweconomy.com.au/a-near-100-per-cent-renewables-g...
(98%/5 hours is for australia and will vary for different countries but probably not wildly).
3) Syngas fills in that last 2-5% with ~50% roundtrip efficiency. Every kilowatt hour used in those 5% times - those dark, windless nights will be quite expensive although, counterintuitively still cheaper than an every kilowatt hour generated by a nuclear power plant - https://theecologist.org/2016/feb/17/wind-power-windgas-chea...
3 and to some extent 2 will require natural gas to be prohibited or taxed heavily.
My google-fu is failing to resurface the links, but IIRC:
One study determined the cheapest energy grids for many countries. IOW, if you had to rebuild the energy grid from scratch today, what would be the cheapest way to meet your needs?
And the answer was 90 - 95% renewables, depending on country. Solar + wind + batteries for 90 - 95% of the power, with natgas peakers for the rest. And that 90-95% number increases every year.
Another survey noted that while Australia and many other equatorial countries are optimal for solar, Finland is pessimal. Most countries have already passed the point where solar is best in pure financial terms. Finland hasn't, but it's very close. Which is insane, given that Finland is a poor place for solar, but a great place for wind, nuclear & geothermal.
Finland does not have any geothermal. The country lies on two billion years old basement rock with approximately zero geothermal activity.
Wind is the dominanting renewable source, with enough of it for Finland to enjoy the second cheapest electricity in Europe last year. And indeed, even solar is profitable, hindered by the winters but helped by the long days during summer.
That is incredible. Why don't they have more power intensive industry as a result?
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One of the reasons I dont expect the australia storage model I cited to be wildly different to, say, Finland is that areas of the world which dont get a lot of sunlight tend to have a lot more wind and hydro potential per capita.
I doubt there are any places in the world where some carbon free combination of solar, wind, hydro, pumped storage, batteries and syngas isnt economic.
Unfortunately, natgas has a large sunk cost advantage. If we were building from scratch in 2025, syngas for the last 2-10% would be competitive. But we have a lot of natgas infrastructure. Syngas's advantage is that it can be locally produced and stored. Natgas has to be shipped large distances, but we already have the infrastructure to do that.
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> 3) Syngas fills in that last 2-5%
Just one note, I believe what you mean is some form of gas made from renewables, most likely hydrogen.
"Syngas" is a term that has a relatively specific meaning in the chemical industry, notably it is a gas mixture of mostly Carbon Monoxide and Hydrogen. I do not think that this is what you mean.